Charge solitons and their dynamical mass in one-dimensional arrays of Josephson junctions

We investigate charge transport in one-dimensional arrays of Josephson junctions. In the interesting regime of “small charge solitons” (polarons), ΛE_J>E_C>E_J, where Λ is the (electrostatic) screening length, the charge dynamics are strongly influenced by the polaronic effects (i.e., by dressing of a Cooper pair by charge dipoles). In particular, the soliton’s mass in this regime scales approximately as E_J^-2. We employ two theoretical techniques: the many-body tight-binding approach and the mean-field approach, and the results of the two approaches agree in the regime of “small charge solitons.” Renormalization of the soliton’s mass could be observed; for example, as enhancement of the persistent current in a ring-shaped array.